Question

Let \(A\) is a \(3 \times 3\) matrix and \(B\) is its adjoint matrix. If \(|B|=64\), then \(|A|=\)
(A) \(\pm 2\)
(B) \(\pm 4\)
(C) \(\pm 8\)
(D) \(\pm 12\)

Answer 1

Ans : (C)
 \(|\operatorname{Adj}(\mathrm{A})|=|\mathrm{A}|^{2}=64 \Rightarrow|\mathrm{A}|=\pm 8\)